In it, but not of it. TPM DC

Did Kirk Break Military Regs With Twitter Posts?

The potential problem, however, is that military regulations strictly forbid active-duty personnel who may be political candidates from engaging in anything campaign-related, even down to "behind-the-scenes activities."

The key questions here are: 1) Whether Kirk's campaign is telling the truth that he did not post the Tweets, but a staffer did; 2) Whether this, too, would violate the rules; and perhaps most importantly, 3) Even if this broke the rules, will anything actually be done against it?